The invention relates to a colour display tube comprising a substantially rectangular display window having an upright edge, a substantially rectangular shadow mask comprising a large number of apertures and a skirt, a substantially rectangular supporting frame to which the skirt of the shadow mask is connected, and suspension means for suspending the supporting frame in the corners of the upright edge.
A colour display tube comprising a shadow mask connected to a supporting frame is disclosed in U.S. Pat. No. 3,368,098. The shadow mask described in said specification is connected to the supporting frame by means of twelve welds. Each side of the shadow mask is connected to the supporting frame by means of three welds, one weld being situated substantially in the centre of the side and the other two welds being situated near the corner of the side at a distance from the centre which is two thirds of the distance between the centre and the corner of the side. Furthermore the supporting frame is suspended in the upright edge of the display window by means of suspension means. Via said suspension means vibrations of the display window can be transmitted to the supporting frame. However, the operation of the colour display tube is adversely influenced by said vibrations of the shadow mask. It has been found in practice that the operation in particular of a colour display tube of which the supporting frame is connected in the corners of the upright edge of the display window is adversely influenced.
It is the object of the invention to provide a colour display tube having an improved operation by damping the detrimental vibrations of the shadow mask.